python二叉树画法

Python中可以使用turtle库来画二叉树，具体实现方法如下：

import turtle

# 定义二叉树节点类
class TreeNode:
    def __init__(self, val):
        self.val = val
        self.left = None
        self.right = None

# 递归画二叉树
def draw_tree(root, x, y, gap):
    if not root:
        return
    # 画节点
    turtle.penup()
    turtle.goto(x, y)
    turtle.pendown()
    turtle.circle(20)
    turtle.penup()
    turtle.goto(x, y-20)
    turtle.write(root.val, align="center", font=("Arial", 12, "normal"))
    # 画左子树
    if root.left:
        x_left = x - gap
        y_left = y - 50
        turtle.goto(x_left, y_left)
        turtle.pendown()
        turtle.goto(x, y-20)
        draw_tree(root.left, x_left, y_left, gap/2)
    # 画右子树
    if root.right:
        x_right = x + gap
        y_right = y - 50
        turtle.goto(x_right, y_right)
        turtle.pendown()
        turtle.goto(x, y-20)
        draw_tree(root.right, x_right, y_right, gap/2)

# 测试
root = TreeNode(1)
root.left = TreeNode(2)
root.right = TreeNode(3)
root.left.left = TreeNode(4)
root.left.right = TreeNode(5)
root.right.left = TreeNode(6)
root.right.right = TreeNode(7)

turtle.speed(0)
draw_tree(root, 0, 200, 200)
turtle.hideturtle()
turtle.done()